IRRITATOR CHALLENGERI, A SPINOSAURID (DINOSAURIA: THEROPODA) FROM THE LOWER CRETACEOUS OF BRAZIL
IRRITATOR CHALLENGERI, A SPINOSAURID (DINOSAURIA: THEROPODA) FROM THE LOWER CRETACEOUS OF BRAZIL
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刺激者挑战者，来自巴西白垩纪下部的棘龙科（恐龙：兽脚亚目）
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发表时间：
2002
期刊：
影响因子：
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通讯作者：
D. Scott
中科院分区：
文献类型：
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作者：
H. Sues;E. Frey;D. Martill;D. Scott
摘要激龙Challengeri Martll等人1996年在巴西东北部桑塔纳组(下白垩统)的罗穆亚尔多成员的正型代表了迄今为止已知的最完整的棘龙头骨。现在完全准备好的标本为这些神秘的食肉恐龙的颅骨结构提供了许多新的信息。头骨非常狭窄，特别是在细长的鼻子区域。上颌骨沿中线广泛接触，形成广泛的次级骨腭部。上颌牙齿有直的或略下弯的圆锥形牙冠，有薄薄的凹槽牙釉质和明显但光滑的隆突。与重爪龙步行龙一样，泪腺的前突和腹突以比大多数非鸟兽脚类恐龙更尖锐的角度相遇。脑壳前后较短，但背侧较深，腹侧向远低于枕骨髁。激龙Challengeri在牙齿结构上与棘龙埃及斑潜蝇最为相似，但由于已知后者的颅骨材料数量有限，目前无法在这两个分类群之间进行更广泛的比较。
Abstract The holotype of Irritator challengeri Martill et al., 1996 from the Romualdo Member of the Santana Formation (Lower Cretaceous) in northeastern Brazil represents the most complete skull of a spinosaurid known to date. The now fully prepared specimen provides much new information on the cranial structure in these enigmatic predatory dinosaurs. The skull is remarkably narrow, especially in the region of the elongated snout. The maxillae are in broad contact along the midline, forming an extensive secondary bony palate. The maxillary teeth have straight or slightly recurved, conical crowns, with thin, fluted enamel and distinct but smooth carinae. As in Baryonyx walkeri, the anterior and ventral processes of the lacrimal meet at a more acute angle than in most non-avian theropod dinosaurs. The braincase is short anteroposteriorly but deep dorsoventrally, extending ventrally far below the occipital condyle. Irritator challengeri most closely resembles Spinosaurus aegyptiacus in the structure of its teeth, but more extensive comparisons between the two taxa are currently impossible due to the limited amount of cranial material known for the latter.